New I-5 bridge will do little to relieve congestion

Local agencies will vote on the I-5 bridge project at meetings that may include public comment.

• Vancouver City Council: Monday

• C-TRAN board: Tuesday

• Portland City Council, TriMet board: Wednesday

• Joint Policy Advisory Committee on Transportation: Thursday

• Metro Council: July 17

• Southwest Washington Regional Transportation Council: July 22

A $4.2 billion project designed to relieve the Interstate 5 bridge bottleneck will in two decades return congestion to about the same level drivers experience today.

Under-30 mph traffic at the new Columbia River bridge will thwart trucks and commuters for 3.5 hours each morning by 2030, up from about two hours today. Thousands driving south into Portland every day will stack up for miles behind the already difficult Rose Quarter bottleneck -- a separate problem altogether.

These are among key findings in a federally mandated environmental study of the Columbia River Crossing project, which proposes to replace the six-lane I-5 bridge with a 12-lane toll bridge, light rail extension to Vancouver and bicycle and pedestrian improvements.

The congestion and travel time findings are likely to come up this week when the Portland and Vancouver city councils and transit agencies for both cities vote on the project.

Bridge planners and elected officials who endorse the project acknowledge such congestion shortcomings. But given the region's forecast of 1 million more residents in the next two decades, they say that ending up with today's level of congestion would be a substantial feat.

Doing nothing, by contrast, would allow catastrophic levels of congestion to ensue. Combined morning and afternoon congestion would nearly triple, growing from about six hours a day today to 15 hours a day in 2030, the environmental study says. A new, high-capacity bridge would show about 5.5 hours of daily congestion in 2030.

Trucking interests -- the I-5 is the West's major north-south artery -- already struggle under bridge congestion, which thwarts delivery schedules. A new bridge that would at least hold things even is considered by shippers to be essential.

But population growth is the biggest challenge. Metro's regional transportation plan forecasts spending $9 billion in the next 25 years across the Portland area - not counting a new I-5 bridge - all the while traffic congestion more than doubles.

There are bright spots. With a new bridge, commuters headed north in the afternoon peak would have nearly free-flowing conditions, a major benefit, says Hal Dingerink, chancellor of Washington State University, Vancouver and co-chairman of a bi-state task force that studied the project.

But southbound commuters would still run into the Interstate 405/I-5 split, a longstanding bottleneck that was beyond the scope of the bridge project, he says.

"We were not equipped or charged to deal with all of the transportation problems here," Dingerink says. "There are other ones, the 405 split being a major one that someone needs to address. There's no question about it."

Still, the travel time estimates have emboldened critics, who say congestion and travel delays could be much worse than forecast.

Tom Buchele, a Lewis & Clark Law School professor representing eight environmental and health groups critical of the proposal, says the bridge project could produce far more congestion.

"It will be worse," Buchele says. "Their main purpose is to reduce congestion. They're spending an awful lot of money and not reducing congestion by that much."

For Clark County commuters who contribute to the rush-hour bottleneck, the bridge project will actually mean a longer commute through a 5.2-mile stretch from 39th Street/State Route 500 in Vancouver to Columbia Boulevard in North Portland.

That area was the focus of bridge planners' attention, because congestion on six interchanges there make bridge congestion worse. Also, more than two out of three motorists using the bridge during morning and afternoon rush hours get on or off I-5 in that 5.2-mile area.

During the 6:30 a.m. to 8:30 a.m. peak of morning rush-hour, it takes a driver 16 minutes to go from SR 500 to Columbia Boulevard, according to the environmental study. Do nothing, and by 2030 that trip would lengthen to 19 minutes, the study says.

Build the proposed 12-lane bridge with light rail and toll charges, and the same trip would take 21 minutes - two minutes longer than doing nothing.

How could adding lanes make a trip longer than doing nothing and allowing stop-and-go conditions to continue?

In short: Leaving I-5 with a six-lane bridge would restrict the hourly volume of traffic over the river, limiting its impact on the longtime bottleneck north of the Rose Quarter.

Just north of the Rose Quarter, I-5 southbound's three lanes split, causing motorists to slow down and weave. I-5 motorists squeeze into two lanes to go farther south. And cars going to I-405 and the Fremont Bridge must fit into two lanes that direction as well.

Though the problem is well-known, the I-5 bridge task force was told by a previous bistate task force to limit its scope to the bridge area and not deal with the I-5/I-405 split, Dingerink says. That's in part because some officials felt the I-5 split problem was more of an Oregon issue, rather than a bistate concern, he says.

But the task force did ask the Oregon Department of Transportation to study the I-5/I-405 split problem last year. Adding a fourth lane from Delta Park to I-405 might reduce the traffic weaving and cost as little as $150 million, officials said. But making that part of the bridge project could require more study and years of delay, bridge planners said.